I found a great source for Zeltbahns (better know as shelter halves or quarters) from a big surplus dealer back in New York, NY. I picked up two Swedish zelts for my BGS bicycle project........... both very used, but very cool.
These zelts are the triangluar shaped quarter shelters and are designed to be combined in groups of 4 with a single center pole to form a full sized "tipi" stlyle tent. They also have a neck hole in the center that can be used to wear the zelt as a poncho. The neck hole can be buttoned closed with a double-overlapping flap to close it off for shelter use.
There are buttons arranged along the edges on both sides to allow the zelt to be buttoned in various configurations when worn or used as a shelter. The camo pattern on these zelts is very similar to the German WW2 style, as is the shape. These Swedish zelts were used from the 1930's to the 80's. One of the zelts I have has the distinctive tripple crown marking on one corner with sewn on buttons........ the other has riveted on buttons. I believe the sewn ones are the oldest.
I have a few repairs to make to the buttons, then this set will be rolled and strapped to the BGS bicycle.
I have an additional set of "like new" Swedish zeltbahns (4 quarter shelters), with the issued pole set on order. I'll post pictures when that set arrives.